Plumbing; Flushing Existing Line Set And Indoor Coil - Lennox HS40 Series Installation Instructions Manual

Plumbing

If the HS40 unit is being installed with a new indoor coil and
line set, the plumbing connections should be made as out
lined in this section. If an existing line set and/or indoor coil is
going to be used to complete the HS40 system, refer to the
following section which includes flushing procedures.
Field refrigerant piping consists of liquid and suction lines
from the condensing unit to the indoor evaporator coil . Use
Lennox L15 series line sets as shown in table 1 or use field−
fabricated refrigerant lines. Refer to Refrigerant Piping
Guide (Corp. 9351−L9) for proper size, type, and applica
tion of field−fabricated lines.
TABLE 1
REFRIGERANT LINE KITS
HS40 UNIT LIQUID
LINE
HS40−018 5/16 in.
HS40−024 (8 mm)
3/8 in.
HS40−036
(10 mm)
3/8 in.
HS40−048
(10 mm)
3/8 in.
HS40−065
(10 mm)
WARNING
Polyol ester (POE) oils used with R407C refrigerant
absorb moisture very quickly. It is very important
that the refrigerant system be kept closed as much
as possible. DO NOT remove line set caps or ser
vice valve stub caps until you are ready to make
connections.
WARNING
Unit contains a NITROGEN holding charge. The hold
ing charge must be purged and the system must be
evacuated prior to charging with R407C.
Plumbing Connections
HS40 Matched with New Indoor Coil and Line Set
If an existing indoor coil which was equipped with an
RFCI metering device is being replaced, the liquid line
must also be replaced prior to the installation of the
HS40 unit.
FIGURE 3
SUCTION L15 LINE
LINE SETS
L15−21
5/8 in.
15−50 ft.
(16 mm)
(4.6 m − 15 m)
L15−41
3/4 in.
15−50 ft.
(19 mm)
(4.6 m − 15 m)
L15−65
7/8 in.
15−50 ft.
(22 mm)
(4.6 m − 15 m)
Field
1−1/8 in.
Fabricated
(29 mm)
If refrigerant lines are routed through a wall, seal and iso
late the opening so vibration is not transmitted to the build
ing.
NOTE − Line length should be no greater than 15.2 m. Se
lect line set diameters from table 1 to ensure oil return to the
compressor.
Brazing Connection Procedure
1 − The end of the refrigerant line must be cut square and its
internal shape must remain round. The line must be free
of nicks or dents and must be deburred (I.D. and O.D.)
2 − Before making line set connections, use dry nitrogen to
purge the refrigerant piping. This will help to prevent ox
idation and the introduction of moisture into the system.
3 − Use silver alloy brazing rods (5 or 6 percent silver alloy
for copper−to−copper brazing or 45 percent silver alloy
for copper−to−brass or copper−to−steel brazing) which
are rated for use with R407C refrigerant. Wrap a wet
cloth around the valve body and the copper tube stub.
4 − Quench the joint with water or a wet cloth to prevent
heat damage to the valve core and opening port.
IMPORTANT − The tube end must stay bottomed in the
fitting during final assembly to ensure proper seating,
sealing and rigidity.
5 − Install the provided thermal expansion valve (ap
proved for use with R407C refrigerant) in the liquid line
at the indoor coil.
6 − Install the provided filter drier (approved for use with
R407C refrigerant) in the liquid line as close as pos
sible to the expansion device. Do not leave the drier
uncapped for more than 10 to 15 minutes prior to
brazing, evacuation and leak testing.
7 − Install the sight glass on the liquid line at the outdoor
unit. Wrap the sight glass with a wet rag to protect it
during installation.

Flushing Existing Line Set and Indoor Coil

IMPORTANT
If this unit is being matched with an approved line
set or indoor coil which was previously charged
with R22 refrigerant, or if it is being matched with
a coil which was manufactured before January of
1999, the coil and line set must be flushed prior to
installation. Take care to empty all existing traps.
Polyol ester (POE) oils are used in Lennox units
charged with R407C refrigerant. Residual mineral
oil can act as an insulator, preventing proper heat
transfer. It can also clog the thermal expansion
valve, reducing system performance and capacity.
Failure to properly flush the system per the instruc
tions below will void the warranty.
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